Some more small refinements

Today we have made a few more little changes to make things more efficient.

1) The ESC key will now cancel out of any editable popup box (dates, repeat, file attachments)
2) If you are not using due time or start time, single clicking on the calendar will now set the date and make the calendar go away.
3) Fixed bug were double-clicking on the "next month" arrow inside the calendar would make the calendar go away.
4) Fixed bug where keyboard shortcuts would be temporarily ignored after editing the repeat value of a task.
5) Searching for tasks using dates in the D/M/Y format will now work.